Clicking only selects surface - Mac

Mac OSX v.4.14.2-3241561+++UE4+Release-4.14

I’m currently following the official Unreal beginner tutorials on YouTube as precisely as possible, and am running into a frustrating issue. The tutorial calls to create walls by copy/pasting Boxes (Geometry > Box). For me, when left-clicking on an item, only the surface is selected and it doesn’t function the same as the tutorial (figured out that Command-Click was the way to select multiples, but still having issues), especially when using a Subtractive Brush Type. If I start each wall from scratch, I can get the Subtractive to work properly, however once placed it can’t be selected again except in the World Outliner. I’ve had two other people follow the tutorial as well (one of whom has trained UE4 experience), all with the exact same results.

I’ve searched through the forums and found other references to what appears to be the same issue, some with fixes, some without. No matter what I try nothing works.
• made sure Subtractive was created after all Additive
• made sure Settings > Allow Translucent Selection was unchecked
• restarted and completely created new project from scratch

Any suggestions?